The Maitrakas of Vallabhi followed after the downfall of Gupta Empire. They followed the same style of Guptas and Western Kshatraps for their coins.
As far as my knowledge goes,
The reverse of silver drachm of Western Kshatraps shows chaitya hill in the centre, with a Brahmi legend around.
The reverse of silver drachm of Guptas shows garuda/peacock in the centre, with a Brahmi legend around.
The reverse of silver drachm of Maitrakas of Vallabhi shows a trident symbol in the centre, with a Brahmi legend around.
So I think the coin at
https://en.numista.com/catalogue/pieces48083.html is not of Kumaragupta.
Also found out that all the coins of Maitrakas of Vallabhi have same ruler name 'Bhattaraka'
You can see nice examples of Kumaragupta coins at
http://coinindia.com/galleries-kumaragupta.html
Also good info on Maitrakas of Vallabhi coins at
http://www.worldofcoins.eu/forum/index.php?topic=21947.0
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